WASHINGTON — Average long-term U.S. mortgage rates rose this week but remain at historically low levels as the Federal Reserve prepares to raise its main borrowing rate.

The average rate on a 30-year loan hit 3.85%, up from 3.76% last week, mortgage buyer Freddie Mac reported today. A year ago, the long-term rate was 3.05%.

The average rate on 15-year, fixed-rate mortgages, popular among those refinancing their homes, climbed to 3.09% from 3.01% a week earlier. It stood at 2.38% a year ago.

Last week, Fed Chair Jerome Powell said he supported a traditional quarter-point increase in the Federal Reserve’s benchmark short-term interest rate when the Fed meets later this month, rather than a larger increase that some policymakers suggested.

Powell opened the door to a bigger hike in the event that inflation, at a four-decade high, doesn’t noticeably decline this year as the Fed expects it to.

The Labor Department reported Thursday that consumer inflation jumped 7.9% over the past year, the sharpest spike since 1982 and likely only a harbinger of even higher prices to come. The increase reflected the 12 months ending in February and didn’t include most of the oil and gas price increases that followed Russia’s invasion of Ukraine on Feb. 24.

Home prices are up about 15% in the past year and as much as 30% in some cities. Available housing has been in short supply even before the pandemic started two years ago, and higher prices and rising interest rates will make it even harder for Americans to secure a new home.